title: Gene-environment processes linking peer victimization and physical health problems: a longitudinal twin study.
abstract: OBJECTIVE
  This study examined whether (a) a genetic disposition for physical health problems increases the risk of peer victimization and (b) peer victimization interacts with genetic vulnerability in explaining physical health problems.
  
  
  METHODS
  Participants were 167 monozygotic and 119 dizyogtic twin pairs. Physical symptoms were assessed in early childhood and early adolescence. Peer victimization was assessed in middle childhood.
  
  
  RESULTS
  Genetic vulnerability for physical health problems in early childhood was unrelated to later peer victimization, but genetic vulnerability for physical health problems during early adolescence increased the risk of victimization. Victimization did not interact with genetic factors in predicting physical symptoms. Environmental, not genetic, factors had the greatest influence on the development of physical symptoms in victims.
  
  
  CONCLUSIONS
  Genetic vulnerability for physical health problems in early adolescence increases the risk of peer victimization. Whether victims suffer a further increase in physical symptoms depends on the presence of protective environmental factors.
authors.affiliation: Department of Psychology, University of Quebec at Montreal, CP 8888, Succ. Centre-Ville, Montréal, Québec, Canada, H3C 3P8. Brendgen.Mara@uqam.ca.
authors.forename: Mara
authors.initials: M
authors.lastname: Brendgen
authors.forename: Alain
authors.initials: A
authors.lastname: Girard
authors.forename: Frank
authors.initials: F
authors.lastname: Vitaro
authors.forename: Ginette
authors.initials: G
authors.lastname: Dionne
authors.forename: Richard E
authors.initials: RE
authors.lastname: Tremblay
authors.forename: Daniel
authors.initials: D
authors.lastname: Pérusse
authors.forename: Michel
authors.initials: M
authors.lastname: Boivin
mesh_terms: D000293:Adolescent; D058445:Bullying / Q000523:psychology*; D002648:Child; D002675:Child, Preschool; D019548:Crime Victims / Q000523:psychology*; D005260:Female; D059647:Gene-Environment Interaction; D006304:Health Status; D006801:Humans; D007223:Infant; D007398:Interpersonal Relations; D008137:Longitudinal Studies; D008297:Male; D010379:Peer Group; D014427:Twins / Q000523:psychology*
keywords: gene–environment correlation; gene–environment interaction; peer victimization; physical health problems; twins